Lamp socket



May 26 1942 J. P. JQRGENSEN 2,283,934

LAMP SOCKET Filed April 28, 1959 @7G/729s Cf engen g.. im

- f Homey/s Patented May Z, 1942 UNITED STATES PATENT OFFICE LAMP socxsrApplication April 28, 1939, Serial No. 270,544

14 Claims.

This invention relates to sockets for small electric light bulbs such asare commonly used on instrument panels and the like.

The general object is to provide such a new and improved lamp socket ofthe above character which is simple in construction and extremelyinexpensive to manufacture, and which effectually encloses all of itsmetal parts as well as those of the light bulb.

A more detailed object is to provide a novel electric light socket inwhich a split metallic member providing side and end contacts isexpanded automatically within an insulating casing and, as an incidentto insertion and such expansion, becomes locked against both axial andangular movement.

The invention also resides in the novel vconstruction which adapts thesocket to bulbs with bayonet type bases and which permits of assembly ofthe parts by automatic expansion of the contact member. l

Other objects and advantages of the invention will become apparent fromthe following detailed description taken in connection with theaccompanying drawing, in which:

Figure 1 is a perspective view of a lamp socket embodying the novelfeatures of the present invention.

Fig. 2 is a longitudinal section, approximately three times actual size,taken along the line 2--2 of Fig. 1.

Figs. 3, 4, 5, and 6 are cross-sectional views taken respectively alongthe lines 3 3, 4 4, 5-5, and 6--6 of Fig. 2.

Fig. 7 is a broken perspective view of the lamp socket casing.

Fig. 8 is an exploded perspective View of the different parts.

Fig. 9 is an elevational view of a modified socket.

Fig. 10 is a fragmentary longitudinal sectional view of anothermodification.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawing and Will hereindescribe in detail the preferred embodiment. It is to be understood,however, that I do not intend to limit the invention by such disclosurebut aim to cover all modifications and alternative constructions fallingwithin the spirit and scope of the invention as expressed in theappended claims.

In Figs. 1 to 8, the invention is illustrated as a socket for a smallelectric light bulb I0 of the metal shell or base I2 constituting theother terminalvand having bayonet joint projections I3. The inventionis, of course, applicable to lamps having screw bases, such adaptationbeing shown in Fig. 10.

The improved socket includes a tube or casing I4 of insulating materialand preferably of generally cylindrical shape. At one end, the tube hasan internal flange I5 of a diameter only slightly larger than the lampbase I2 and tapering as indicated at I6 toward the tube end toiacilitate entry of the lamp base. Slots I1 on diametrically oppositesides of the iiange extend throughout the length of the latter and areadapted to receive the projections I3 when used in connection with abulb of the bayonet type.

The inner end I8 of the iiange I5 and the upper end surface I9 of asimilarly sized iiange 20 coact to define an annular groove 2| in whichis seated a contact carrying member 22 which is split longitudinally soas to be radially expansible and contractible. Herein, this membercomprises a sheet of resilient sheet metal such as steel bent intogenerally U-shape and having a substantially fiar, closed end 23 and twocontact arms upstanding therefrom and preferably curved to conform tothe external shape of the bulb base with which the socket is to be used.

These arms coact to form the socket proper and are of steppedconstruction, each having portions 24 smaller than the internaldiameters of the flanges I5 and 20 so as to passfreely therethrough.Intermediate their ends, the arms are bent outwardly to provide offsets25 which space the free ends 26 of the arms apart a distance somewhatgreater than the .internal diameter of the flange I5. The ends 26 areshorter than the axial length of the groove 2| so that when the member22, while radially contracted at its open end, is inserted closed endfirst through the `flange I5 and moved past the latter, the ends Toprevent turning of the socket member when thus seated, lugs 2l struckout of the offsets 25 on diametrically opposite sides of the socketconstitute extensions of the ends 26 and project downwardly into notches28. The latter are formed in the flange 20 in longitudinal alinementwith the slots I1 so that the lugs 21 type having an end terminal Ilinsulated from a will enter properly as an incident to insertion of thesocket member into the tube with the lugs in proper alinement with theslots I1.

Slots 30 are formed in the upper free ends of the contact ends 26parallel to the axis of the member 22 and in longitudinal alinement withthe lugs 21. At their lower ends, the slots communicate with slots 29which extend circumferentially in opposite directions. The slots 29 and30 cooperate with the projections I3 on the bulb to provide a bayonetjoint.

A hole 33 punched in the closed end 23 of the socket member receives aninsulating shouldered washer 34 which is fastened to a washer 35 on theother side of the end 23 by an eyelet 35* the ends of which are expandedafter insertion. Projecting slidably through the eyelet and insulatedfrom the member 22 by the washers is a contact pin 36 of relatively softmetal having a flange 31 which abuts against the under side of thewasher. After entry of the pin, its hollowed upper end is forged orsplayed to form a iiange 38 which is adapted to abut against the endterminal II of the bulb. A spring 39 coiled about the pin 36 between thewasher 36 and the ange 38 acts in compression to urge the pin upwardlyand hold it yieldingly against the bulb contact. The lower end 40 of thepin is bifurcated to receive the bared end 6I of a covered conductor 42which is soldered to the pin. The other conductor i3 is attached as bysolder 44 to the outer side of one socket portion 24. If desired, thepoint of attachment may be immediately beneath one of the lugs 21 sothat the solder and the conductor will be disposed in one of the notches2B in the assembled socket. Being The lower end 45 of the tube extendssub-' stantially beyond the contact pin 36 so that all of the metalparts are fully concealed. This end has an opening 46 through which4 theconductors extend and which is of smaller internal diameter than thetube proper.

To provide a simple means of attaching the tube I4 to a mounting bracket4l, the tube end 45 is made of reduced diameter and molded withlongitudinal spline grooves 48. The end is received snugly in a hole 49in a flange 50 on the bracket 41. ,Spaced around the hole are inwardlyprojecting lugs I which are slightly wider than the spline grooves 48.By pressing the tube into the hole 49, the teeth 5I are forced throughthe grooves 48 and become locked therein with a tight friction t as theange 50 comes into abutment with the enlarged part of the tube.

The tube I4, while constructed to perform.

numerous functions in conjunction with the socket member and themounting bracket, is relatively simple to manufacture. Except for thegroove 2|, it can be molded easily from resinous insulating material andformed as a unitary piece. The groove is cut in the tube by a simpleinternal turning operation. Or, by splitting the tube I4 longitudinally,the groove 2| may be formed in a molding operation. In such a case, twoparts I4 and I4b would be formed as shown in Fig. 9

and held together as by a contractible metal ring 55, the end 45 of thesplit tube being splined into the mounting bracket 41 as previouslydescribed.

In the assembly, the pin 36 is iirst mounted on the socket member 22 andthe conductors 42 and 43 are attached. Then, after threading theconductors through the tube, the member 22 is inserted through thelarger end of the tube with the lugs 21 properly alined with the slotsI1 and the arms 28 contracted together so as to pass through the flangeI5. As the upper ends of the arms 26 pass the-shoulder I3, the armsexpand automatically into the groove and the mem-- ber 22 becomes lockedeil'ectually between the shoulders I8 and I9. At the same time, the lugs21 enter the notches 23, thereby fastening the member 22 against turningwithin the tube.

To iit a light bulb into the socket, the base l2 is inserted in the tubeand turned until the projections 23 register with and drop into theslots l1, such entry being facilitated by the taper I6. The bulb is nextpushed inwardly past the iiange I5 and past the position at which theend terminal II engages the end 38 of the contact pin 36. In thismovement, the projections I3 enter and follow down along the slots 30which are held by the lugs 21 in accurate alinement with the slots I1.After the projections encounter the lower deiining edge of the slots 29,the bulb is turned in the proper direction to move the projections alongtheir slots to the closed ends thereof. In this nal position, the spring39 serves to maintain proper contact between the projections I3 and themember 22 as well as between the pin 36 and the end terminal II. Toremove the bulb, it is only necessary to turn it in the reversedirection until the outer defining side of the slots 30 are encounteredby the projections I3 which will then be alined accurately with theslots I1 to permit withdrawal of the bulb.

To adapt the socket member 22 for use with electric bulbs of the screwbase type, threads 5B (Fig. 10) are rolled in the ends 26 of the contactarms. In such a case, anges 51 are formed at the upper ends of the armsto engage the bottom of the groove 2| and space the threads for properengagement with the threads on a bulb base inserted through the tubeange I5. Also.

the lugs 21 would be disposed to similarly space the lower part of thecontacts 26 away from the bottom of the groove 2|.

I claim as my invention:

1. A socket for an electric light bulb having a cylindrical base andbayonet projections thereon comprising, in combination, a tube ofinsulation having an internal ilange at one end for receiving andenclosing said bulb base, longitudinal slots in said iiange receivingsaid projections when said base is inserted into said end, a secondinternal flange within said tube spaced from said first iiange andcooperating therewith to forma peripheral groove, notches in said secondflange longitudinally alined with said slots, a U- shaped contact memberof resilient metal within said tube having its closed end projectingbeyond said groove and its open end of larger diameter expanded into thegroove whereby the member is coniined axially by said flanges, lugs onsaid` enlarged end projecting into said notches to hold the memberagainst turning relative to said tube, said enlarged end having bayonetslots communicating with said slots and adapted to receive saidprojections, an insulating washer mounted in an aperture in the closedend of said member, a contact pin extending through and slidable axiallyin said washer, and a compression spring coiled around said pin withinsaid member and urging the pin against the end contact of said bulb whenthe latter is seated in said bayonet slots.

2. A socket for an electric light bulb having a cylindrical base andbayonet projections thereon comprising, in combination, an open endedtube of insulation having an internal peripheral groove, longitudinalslots in said tube extending to the groove from one end of said tube, anotch in said tube at the other end of the groove and longitudinallyalined with one of said slots, a U- shaped metal socket member having anenlarged open end expanded into said groove whereby the memberisconfined axially, said enlarged end having bayonet slots communicatingwith said slots and adapted to receive said projections, a lug on saidenlarged end projecting into said notch to hold the member againstturning relative to -said tube with said bayonet slots in register withsaid first mentioned slots, and an insulated contact mounted at theclosed end of said member for engagement with the end contact of saidbulb when the latter is seated in said bayonet slots.

3. A socket for an electric light bulb having al bayonet contactprojection on its base, said socket comprising, in combination, a tubeof insulation having axially spaced internal shoulders, a longitudinallysplit lmetallic socket member of diierent diameters at opposite ends,the larger end being expanded between said shoulders so as to beconfined axially thereby and being adapted to receive said base of saidbulb inserted through one of said shoulders, a b-ayonet slot in saidlarger end adapted to interengage with said projection when the bulb isinserted in said socket, means on said tube and member interengageableautomatically as an incident to insertion of the member in the tube tolimit relative turning of the two, and a contact mounted on andinsulated from the smaller end of said member and engaging the endcontact of said bulb when said projection and slot are interengaged.

4. A socket for an electric light bulb having a base with bayonetprojections thereon comprising, in combination, a tube of insulationopen at one end and providing two internal shoulders facing each otherin opposed relation, a U-shaped contact member having two relativelymovable contact fingers and adapted when contracted at its open end tobe insertable in one end of said tube, said member having an enlargedopen end adapted to be expanded into said groove whereby the member isconned axially by said shoulders, interengaging elements on said tubeand member holding the member against turning relative to said tube,said enlarged end having bayonet slots adapted to receive saidprojections, and a contact mounted on and insulated from the closed endof said'member to engage the end contact of said bulb when the latter isseated in said bayonet slots.

5. A socket for an electric light bulb comprising, in combination, atube of insulation having an internal flange at one end for receivingand enclosing the base of said bulb, a second internal flange withinsaid tube spaced from said first flange and cooperating therewith toform 'a peripheral groove, a notch in said second ange, a resilientU-shaped contact member disposed within said tube and having an enlargedopen end expanded into said groove whereby the member is conned axiallyby said flanges, a lug on said enlarged end projecting into said notchto hold the member against turning relative to said tube, said enlargedend when thus seated providing a socket for the base of said bulb, aninsulating Washer mounted in an aperture in the closed end of saidmember. a contact pin extending through and slidable axially in saidwasher, and a compression spring coiled around said pin within saidmember and urging the pin against the end contact of said bulb when thelatter is seated in said member.

6. A socket for an electric light bulb having a base with contactterminal formations thereon, said sockets having, in combination, arigid tube of insulation open at one end and having longitudinallyspaced internal shoulders facing each other, a resiliently expansibleContact member inserted through said end past said shoulders andexpanded therebetween so as t0 be confined axially, meansinterengagcable automatically as an incident tb endwise insertion ofsaid member in said tube and acting to hold the member against turningrelative to the tube, said member providing a socket for receiving thebase of said bulb and having formations thereon interengageable withsaid base formations to fasten the base in said socket, and an insulatedcontact mounted on said member and yieldably engaging the end contact ofsaid bulb when the bulb is seated in the member. l

7. In a lamp socket, a U-shaped sheet metal piece having an aperturedclosed end and upstanding parallel arms with their free ends offsetoutwardly relative to their connected ends, said free ends havingbayonet slots formed therein and extending longitudinally from the upperends of said arms and then transversely, a lug struck out from at leastone of said arms and constituting an extension of one of said free ends,an insulating washer mounted in the aperture of said closed end, acontact pin extending through and slidable in said washer, and a springcoiled about said pin and acting between said closed end and the pin tourge the pin toward the open end of said piece.

8. In a lamp socket,\a U-shaped sheet metal piece having upstandingparallel arms with their free ends substantially parallel and offsetoutwardiy and laterally from their connected ends, said free endsproviding a longitudinally split yieldably expansible socket forreceiving the base of an electric light bulb, formations on said freeends within said socket and interengageable with said light bulb base,and a contact pin insulated from and slidably mounted on the closed endof said piece.

9. A socket for an electric light bulb having, in combination, a rigidtube of insulation having inturned shoulders at one end defining betweenthem a slot extending longitudinally of the tube, a U-shaped Contactmember insertable into said tube past said shoulders and havingresilient free ends adapted to expand automatically behind saidshoulders after passing the latter when the member is inserted in saidtube, a bayonet slot in one 0f said free ends opening longitudinallythereof and elements on the tube and member interengaglng automaticallyas an incident to insertion of said member in said tube and coacting tohold said tube and member against turning with said slots inlongitudinal alinement.

10. A socket for an electric light bulb having, in combination, a rigidtube of insulation having inturned shoulders at one end, a U-shapedcontact member resiliently contractible at its open end so as to passsaid shoulders when the member is inserted in the tube and expandautomatically behind said shoulders after passing the latter, saidmember being fashioned for intersaid tube whereby to grip said bulb andhold the same removably in said member, and an insulated contact mountedon said member for engagement with the end contact of said bulb.

11. A. socket for an electric light bulb comprising, in combination, aresiliently' expansible contact member of U-shape having two legs spacedapart at the open end a greater distance than at the closed end. a rigidtube of insulation enclosing said member and engaging the same to holdthe member against axial and turning movement, a contact insulated fromand slidably mounted on the closed end of said member for yieldableengagement with the end contact of a lamp bulb base inserted in saidopen end, and a conductor lying alongside one of said legs adjacent saidclosed end and electrically connected to the member.

l2. In a lamp socket, a U-shaped metal piece having a closed end andupstanding parallel arms with their free ends offset outwardly relativeto their connected ends, formations on said free ends adapted forinterengagement with the base of a lamp bulb, a lug rigid with saidpiece and disposed alongside the connected ends of the piece, aninsulated contact supported on said closed end for engagement with theend of a lamp bulb supported by said piece, and a tube of insulationsurrounding said piece and having means interengageable with said lug tohold the piece and tube against turning relative to each other.

13. A socket for an electric light bulb having,

in combination, a rigid tube of insulation having lnturned shoulders atone end, a U-shaped contact member resiliently contractible at its openend so as to pass said shoulders when the member is inserted in the tubeand expand automatically behind said shoulders after passing the latter,said member being fashioned for interengaging contact with a light bulbinserted in said tube whereby to grip said bulb and hold the sameremovably in said member, an insulated contact mounted on said memberfor engagement with the end contact of said bulb, and means renderedactive in the insertion of said member in said tube to interconnect thetube and member and hold the two against relative turning.

14. A socket for an electric light bulb having, in combination, a rigidtube of insulation having an lnturned shoulder near one end, a generallyU-shaped resiliently expansible contact member inserted closed end firstthrough said tube end past said shoulder and expanded behind the latterwith the extreme end of at least one leg of the member abutting againstthe shoulder whereby the member is locked positively against withdrawalfrom the tube, formations on the free ends of said memberinterengageable with the base of said light bulb to grip said base andhold the same removably in the member, and an insulated contact mountedon said member for engagement with the end contact of said bulb.

JAMES P. J ORGENSEN.

